Pressure regulating system



May 27, 1941. D- GREG@ 2,243,627

- PRESSURE REGULATING SYSTEM Filed April 18, 1940 Daz/fd Gre y Patented May 27, 1941 miam PRESSURE REGULATING SYSTEM David Gregg, Caldwell, N. J., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application April "18, 1940, Serial No. 330,385

14 Claims.

The present invention relates to the subject of pressure regulation and more particularly to the regulation of pressure of the fuel and air mixture in the intake of an internal combustion engine.

Internal combustion engines for aircraft are subject to a wide range of input pressures, parF ticularly due to the wide range of altitude traversed in normal ight,-and also because of the variation in pressure which is the result of nonuniform supercharger action.

In the past, attempts have been made to regulate the supercharger, both manuallyv and automatically, but none of these attempts, up until the present invention, have been successful in producing a thoroughly reliable and simple automatic device for the regulation of intake pressures.

One of the objects of the present invention lies in the provision of a pressure regulator for automatically maintaining, over a wide limit of intake pressure variations, a constant manifold pressure in an internal combustion engine.

Another object of the present invention resides in the provision of a regulator, in a system subject to pressure variation, that will automatically maintain a preset pressure through a novel pressure sensitive and servo-motor system.

Other objects of the invention include the provision of a pressure regulating system, which is set into operation by manipulation of the conventional hand throttle and which employs a novel servo-motor system for maintaining manifold pressure constant, and also, the provision of a novel means in an automatic pressure regulating system for permitting the operator to override or overpower the servo-system merely by manipulation of the hand throttle.

Other objects of the present invention will appear from the following specification when studied in conjunction with the attached drawing, in which there is shown, partly in cross-section and partly schematic, a pressure regulating system of the present invention as applied to the input manifold of an internal combustion engine.

'I'he present invention, as applied to internal combustion engines, particularly those adapted for use on aircraft, includes the conventionalthrottle to obtain a desired manifoldl'pressure and' releases the hand throttle, the device of the present invention will automatically vary the throttle for changing input pressures in order to maintain the manifold at the present value.

Further, if the pilot desires to change the manifoldl pressure at any time, he may accomplish this end by merely moving the hand throttle to the position which gives his his newly desired manifold pressure, and upon release of the hand throttle, this new pressure will be automatically?- maintained by the novel device of the present invention, which is described below.

The intake manifold is shown generally at l0, at one end of which is a conventional carburetor I I having an air intake scoop I2 and a fuel mixing chamber I3. A throttle valve I4, of conventional design, is disposed Within manifold I0 and is connected through a suitable linkage I5 to a hand throttle lever I6. Asupercharger I'I is connected in manifold I0 at some point posteriorly of care buretor II. Engine manifold I0 connects to a conventional aircraft engine, not shown. Supercharger I1 is driven through a suitable gear system I9 by means of the aircraft engine.

At the pilots position there is provided a manifold pressure gauge 20 of any ordinary design,l which isconnected to manifold I 0 by tubular conduit 2l. A servo-motor 22, which includes a cylinder 23, a piston 24, and a piston rod 25, is

Aconnected directly as shown, by means of any suitable linkage, to hand throttle I6. 'I'his servomotor is preferably actuated by oil pressure from the internal combustion engine, from-which oil is led into servo-motor 22 through a suitable conduit 26. Movement ofv piston 24 is controlled by valves 21 and 28, rigidly linked together by bar member 29 to form a two-way valve system. With valves 21 and 28 positioned as shown in the drawing, oil from conduit 24 is introduced t0 cylinder 23 through port 30 which has been uncovered by movement of valve 23 to the right of its neutral position directly over port 30. 'I'he pressure of oil through this port will force piston 24 to movegto the left, forcing oil out of cylinder 23 through port 3| and into an oil sump, not shown, through drain port 32. Movement of servo-motor to the left, will cause hand throttle I6 to move to the left, opening throttle member I4 and increasing the manifold pressure.

It will |be readily seen that movement of Valve 2'I to the leftl of its neutral position, directly above port 3l, will cause oil under pressure to be introduced into cylinder 23 through port 3l, forcing piston 24 to move to the right, simultaneously discharging oil through port 3| and to the oil sump,.not shown, through port 23. Upon movement of piston 24 tothe right, hand throttle l will be moved to the right, tending to close throttle valve I4-and effect `n. reduction in the 4 which point piston rod 25 is loosely connected by means of a pin to lever I5. Rotation of lever I5 about point 3l causes point I4 to be advanced through an arc limited by the movement of block 55 in thehousing 51. As shown in the drawing, hand throttle member I5 is in a position indicating that the hand throttle I4 has been pulled to the rightand that the pilot or operator is still pulling the hand throme to the nght. Thiais evidenced by the fact that block I5 has been moved against thev action of coil spring 35 into abutting relation with the left-hand wall of housing I1. When hand throttle I5 is not being manually moved, block 35 assumes a neutral position, with its end-faces equi-distantly spaced from the left and right end-walls of housing 21, and springs l5 and 35 will be under equal ten sion, tending to maintain block in such neutral position. Block has rigidly attached thereto, a rod member 45, carrying three valve members 4|, 42 and 42, rigidly spaced along the length of rod member 45. A

When lever member l5 is not being manually operated, valve members 4|, 42 and .43 assume positions directly over the openings of passageways 44 and 45, maintaining these passageways closed. However. in the position shown, valve e member 4| has been moved to the leftof the opening of passageway 44 and permits communication of oil to both sides of piston 24. The drawing shows that servo-motor 22 is out of control, since any oil admitted to cylinder 23,

through either of ports l5 and 3|, will be immediately by-passed around piston 24. In this condition, operation of throttle lever I5 is permitted without interference of the servo-motor 22. Y v

Simultaneously with the disabling or overpowering of servo-motor 22 oil is permitted to flow, under manifold pressure, from a reservoir 45 which communicates through a conduit 41 with intake manifold Il. Oil passes from reservoir 45 through tubular conduit 45 and through passageway 45 into conduit 50,' which communicates with the cylindrical chamber 5|, having therein a piston 52 and piston rod 53.

Housing 54 contains a e'xible, metal chamber 55, having a corrugated shell or body portion, such as a Sylphon, having sealed endwalls and partitions 55 and 51. Chamber 55 is secured to the wall of housing 54 by any conventional means, such as a nut and bolt 55, as shown. Chamber 55 may be sealed at any desired pressure, -but preferably under a vacuum, and within the chamber is a coiled spring 59 which tends to expand the walls of chamber 55 and increase the effective pressure at which the chamber is sealed,

member 54, which maintains a duid-tight seal about piston rod 5I. By means of a connector, such as screw 55, a coiled spring 65 is attached to end-wall 51 and the other end of spring 55 is connected to the extremity of piston rod 52. End-wall or partition 51 is provided with an arm 51, which is connected toa rigid link member 55 by means of any conventionalhinge connection 55. Link member 5I is securely fastened to bar member 25.

Chamber 5| has an aperture 15 toV which is aiiixed a conduit 1| communicating with intake manifold I5 at point 12.

The preures within the three chambers 55, 5|, and 5| are such that at any arbitrary manifold pressure desired, the system is in complete balance, that is, there is no movement of partltion 51, and thus, valves 21 and 25 are in their normal position sealing ports 3| and 30, respectively. In this balanced condition, the effective pressure within chamber 55 is due to the combined effect of the gas Ipressure within chamber 55, and the mechanical force exerted by coil spring 55. `If chamber 55 is completely evacuated, then the effective pressure is solely that exerted by spring 55. To this pressure there is added an adjustable pressure element, namely, a coil spring 45 having a tension value which, depending upon the position of piston 52 in chamber 5|, will aid the effective pressure in chamber 5| and tend to draw end-wall or partition 51 to the right. However, with the same manifold pressure in chamber 5| that exists in chamber 5|, when the latter is sealed, movement of partition 51 to the right is prevented, and the tension of spring 55 is sulcient to hold end-wall 51 from moving to the left, thus acting to keep valves 21 and 25 closed. When, however, a cer-I for a purpose to be described later. End-wall Y 51 also acts as an end-wall or partition for another chamber which comprlses a flexible, corrugated, metallic shell member 5|, such as a Sylphon bellows.

-chamber 5| and is surrounded by a packing tain manifold pressure has been introduced to chamber 5|, passageway 45 is closed by means of valves 42 and 45. Amr change of manifold pressure will be reflected .in chamber 5|, which is continuously open to manifold pressure, and if manifold pressure decreases, endfwall 51 will move to the right, carrying valves 21 and 2l to the right of ports 2| and 20, respectively, as shown in the drawing, allowing oil from the engine pump to be introduced through port 5| into cylinder 23 and move hand lever i6 to the left. 'Ihis action will, in turn, tend to open throttle valve I4 and restore the preset manifold pressure to chamber 5|'. If, however, the manifold pressure in chamber 5| increases over that in chamber 5|, wall 51 will move to the left and cause valves 21 and 25 to move to the left of ports 3| and 30, respectively, admitting oil under pressure into cylinder 23 through port 3| and forcing piston 24 to move to the right, closing throttle valve I4 and decreasing the manifold pressure by an amount suiiicient to reestablish the original pressure set in chamber 5|.

Any manifold pressure which the pilot chooses, by manipulation of lever l5, can be maintained automatically by the balancing of pressures in chambers 5|, 55, and 5|, in the manner above described, so that automatically, any variation in chamber 5| from the established pressure in chamber 5| will cause movement of wall 51 and consequent operation of servo-motor 22 to restore the intake manifold to the pressure set in chamber 5|. In accordance with the present invention, therefor,.the pilot always has control of manifold pressure and throttle valve setting, and the desired manifold pressure is automatically maintained, yet no override or lock-out 2,243,6ar l positions for the throttle lever, or any second lever, are necessary, as the pilot may instantly overpower the servo-motor and the rest` of the automatic system by mere manipulationv of the l energy, or of fluid pressure available may be Y utilized. Further, while supercharger l1 is shown as part ofthe system, and while the description makes reference to the regulation of supercharger pressure, it is obvious that the novel invention of the present system is useful with an intake manifold not having provision for supercharging, and also, the pressure regulation system of the present invention may be used to regulate fluid pressures other than intake pressures of internal combustion engines. By means of the present invention, the fluid pressure in any conduit carrying a liquid or gas can be automatically regulated. Engine manifold pressure can, of course, be regulated by controlling the speed of the supercharger, or by varying valves placed at the input and the output of the supercharger, as

well as by governing the movement of a carburetor throttle valve. The invention is not restricted, therefore, to'the particular drawing and description chosen to represent one embodiment thereof, and it is not intended that the invention be limited by the description and drawing, but solely by the scope of the appended claims.

What is claimed is:

1. In a regulator of manifold pressure for internal combustion engines, an intake manifold, a throttle valve in said intake manifold, a hand throttle formoving said throttle valve, a servomotor for controlling the movement of said hand throttle, valve means associated with said hand throttle to effect overpowering of said servomotor, a multiple pressure chamber device having one chamber open to manifold pressure, a

. third chambers to balance the pressure in said second pressure chamber when said third pressure chamber is open to manifold pressure, and valve means for operating said throttle valve through said servo-motor upon change of manifold pressure during intervals when said third chamber is closed to manifold pressure, whereby a predetermined manifold pressure will be maintained regardless of the tendency of manifold pressure to change due to conditions other than throttle valve setting.

3. In a pressure regulating system wherein a predetermined pressure may be manually set and automatically maintained, a fluid conduit in which the pressure is to be maintained, a valve therein, manual means for adjusting said valve to obtain the desired pressure, a servo-motor for adjusting said valve through said manual means, means responsive to the manual adjust- 4. In a pressure regulating system, a conduit,

the pressure of which is to be regulated, a first valve therein, a mechanism including both automatic and manual means for adjusting the pres- 'automatic means including a servo-motor con- .nected to said valve, a iirst chamber open to second chamber sealed at a predetermined prestiple chamber pressure device to actuate saidservo-motor during periods of pressure unbalance to vary the opening of said throttle valve and thereby maintain the manifold pressure constant regardless of changes in manifold pressure due to conditions other than throttle valve setting.

2. In combination with the intake manifold 0f an internal combustion engine, a throttle valve therein, a manually operable member for vsetting said throttle valve, a servo-motor connected to control movement of said manually operable member, means initiated by manual movement of said manually operable member to overpower said servo-motor and to restore said servo-motor upon cessation of manual movement Y of said member, a first pressure chamber open to manifold pressure, a second pressure chamber sealed at a predetermined pressure, a third pressure chamber selectively open and closed to manifold pressure, means connected between said first and conduit pressure, a second chamber sealed at a predetermined pressure, a third chamber having means for effecting mechanical balancing of said first and second chambers at desired conduit pressures, a second valve associated with said chambers so as to be movable between conditions of mechanical balance to operate said first valve through said servo-motor and/maintain the pressure of said conduit constant, and said manual means including a hand lever connected through suitable linkage to said rst valve and having means operable upon manipulation, thereof to overpower said automatic means.

5. In combination with the intake manifold of an internal combustion engine, a supercharger, means for regulating the-pressure delivered thereby to said manifold, comprising a throttle valve, a throttle lever for adjusting said valve, a servo-motor connected to said valve through said throttle lever, means responsive to changing manifold pressure to operate said servo-motor and said throttle valve to restore the desired manifold pressure, and means connected to said throttle lever. to overpower said servo-motor and permit a change of manifold pressure by manual operation of said throttle lever.

6. In va system for automatically regulating the iuid 'pressure in a conduit and for manually setting desired pressures, a conduit, a valve therein for adjusting the pressure in the conduit, a

lever associated with said valve, a servo-motor connected to said lever, and means actuated by manual operation of said lever to disable said servo-motor and upon cessation of manual operation to restore control of said lever to said servo-motor, whereby any manually selected conduit pressure will be automatically maintained.

7. In combination with the intake manifold of an internal combustion engine, a pressure throttling member within said manifold, a manual adjuster of said member connected thereto, a servo-motor for operating said manual ad- Juster, means responsive to changes in manifold pressure for adjusting said pressure throttling member through said servo-motor and means associated with said manual adjuster and responsive to manual adjustment thereof to disable said servo-motor, whereby a desired manifold pressure may be selected, and automatically maintained.

8. In combination with the intake manifold of an internal combustion engine, a member for throttling the pressure within said manifold, means for adjusting said member, a servo-motor for controlling said means, a mechanism responsive to changes in manifold pressure for adjusting said member through said servo-motor, and means assocated with the first-named means for disabling said servo-motor and enabling a manifold pressure to be set independently of said servo-motor.

9. In combination with the intake manifold of an internal combustion engine, a regulator of supercharger pressure, comprising a throttle valve in said manifold, a lever connected thereto, a`servo-moto'r adapted to control said throttle valve through said lever, a rst pressure chamber open to manifold pressure, a second pressure chamber, sealedat a desired pressure, said chambers having flexible walls with a common end-wall movable under conditions of unbalance between the pressures in said flrst and second chambers, a third chamber having rigid walls and an opening in one wall, a piston within said chamber, a piston rod connected thereto and extending through the opening in said wall and into said first chamber, a packing member about said piston rod adapted to'seal said third chamber, a spring member connected to said endwall and to said piston rod, a two-way valve connected to said end-wall and movable during changes in manifold pressure to operatesaid servo-motor, and means actuated by manual operation of said lever to overpower said servomotor and to open said third chamber to manifold pressure, said means, upon cessation of manual operation of said lever, acting to restore control to said servo-motor and to seal said third chamber at manifold pressure, whereby any changes in manifold pressure will unbalance the pressures in said chambers and actuate said servo-motor through said two-way valve.

10. In combination with the intake manifold I of an internal combustion engine, a regulator of manifold pressure including a throttle valve, a hand lever connected to said throttle valve, a servo-motor connected through suitable linkage to said hand lever, a two-way valve capable of urging the servo-motor to increase or decrease manifold pressure through control of said throttle valve, and means for controlling the operation of said two-way valve, said means including an element connected to said two-way valve, a flexible chamber open to manifold pressure, a flexible compartment sealed at a predetermined pressure and a connection common to said exible compartment and said flexible chamber and to said two-way valve for governing operation of said servo-motor.

11. A regulator of manifold pressure for internal combustion engines, comprising a housing, a first pressure chamber thereinsealed at a predetermined pressure value and having a tubular, flexible shell, a second chamber having a tubular, flexible shell, a common end-wall between said chambers, said second chamber be1 ing open to manifold pressure,a third chamber having a rigid shell member, valve means for opening and closing communication of said third chamber to manifold pressure, a piston within said third chamber, a piston rod extending from said piston through a fluid-tight seal into said second chamber, resilient connecting means interposed between said common end-wall' and said piston rod, said common end-wall being movable when the effective pressures in said nrst and second chambers are unequal, the pressure in said third chamber being additive to that in said first chamber to balance the pressure in said second chamber at different manifold pressures, and means responsive to movement of said common end-wall during intervals of pressure unbalance to rebalance said pressures.

' ing range of the device, means common to said first and third chambers to balance `the pressure in said second chamber, a servo-motor adapted to be connected to a pressure regulating valve, and means associated with said flexible elements of said flrst and second chambers to control the operation of said servo-motor.

13. A regulator of intake manifold pressure for an internal combustion. engine including a throttle valve actuating member, a servo-motor connected thereto, means responsive to changing manifold pressure for operating said servomotor to maintain the manifold pressure constant, and means operable upon manual movement of said throttle valve actuating member for disabling said servo-motor and for restoring said servo-motor upon cessation of manual movement of said member.

14. In a regulator of manifold pressure, a servo-motor having a hand throttle engaging member and a source of energization, valve means for controlling the action of said servomotor, a chamber having a port for communication with a manifold and a movable element connected to said valve means, means subject to changing manifold pressure for moving said valve means and operating said servo-motor, said last-named means being operative upon changes in manifold pressure to return the manifold pressure to its desired value, and a hand throttle operated means associated with said servo-motor for disabling said servo-motor upon operation thereof.

DAVID GREGG. 

